The present invention relates to a device for automatically changing a jaw of a chuck of a machine tool.
So far the changing of jaws of a machine tool chuck has been carried out manually, but it takes a long time to change the jaws, which is one of the important factors degrading productivity. Recently, in order to save labors, thereby improving productivity, the demand for the full automation of machine tools including their peripheral equipment has become increasingly high. To this end, various devices for automatically changing jaws of a chuck have been proposed. For instance, U.S. Pat. No. 4,532,692 issued Aug. 6, 1985 disclosed an automatic chuck jaw changer which is compact in size and light in weight. Thus chuck jaw changer has one magazine in the form of a turntable for storing therein jaws, and the number of sets of jaws to be stored is small. Furthermore, U.S. Pat. No. 4,587,708 issued May 13, 1986 discloses an automatic chuck jaw changer which is relatively large in size as compared to the above-mentioned automatic jaw changer and includes a jaw magazine in the form of a cylinder or drum so that the number of sets of jaws to be stored is increased. However, recently various machining operations are carried out so that the number of jaws to be stored and changed is increased and even the above-mentioned automatic jaw changer having the magazines with increased capacity cannot satisfy the demand for carrying out various machining operations. Furthermore, from the viewpoint of the installation space and other factors, it is almost impossible to increase the size of the magazine with a view to increasing the number of sets of jaws to be stored and changed.